Credentialing Results from the RPC’s Spine

Anthropomorphic Phantom

Andrea Molineu, Paola Alvarez, Nadia Hernandez, Fang-Fang Yin,

and David FollowillAugust 2012

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lung

lung

heart

Spine phantom

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lung

lung

heart

Spine phantom

PTV

bonespinal cord

esophagus

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RTOG 0631

• Phase II/III study of IGRT/SBRT

for localized spine mets

• Facility Questionnaire

• IGRT credentialing

• Phantom credentialing

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Treatment Plan• 6 Gy to at least 90% of PTV

• Min PTV dose at least 5.25 Gy

Normal structure

Volume Volume Max (Gy)

Max Point Dose (Gy)

Spinal Cord <0.35 cc<1.2 cc

3.752.63 5.25

Heart <15 cc 6.00 8.25

Esophagus <5 cc 4.46 6.00

Skin <10 cc 8.63 9.75

Whole Lung 1000 cc 2.78CPR

Representative Treatment Plan

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Criteria

• TLD±7%

• Film (axial and sagittal planes)85% meet 5%/3mm

• Plan DVHmust comply with protocol

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Criteria

• TLD±7%

• Film (axial and sagittal planes)85% meet 5%/3mm

• Plan DVHmust comply with protocol

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Good Agreement

PlanMeasurement

PTV

Cord/boneOAR

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Good Agreement

Gamma

Measurement100%

passing

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Poor AgreementPTV

Cord/boneOAR

Measurement Plan CPR

Poor Agreement

Gamma

Measurement100%

passing26%

passing

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Overall results

• 138 irradiations at 98 institutions

• 44 irradiations failed

• 1 failed TLD criteria only

• 29 failed gamma criteria only

• 14 failed both TLD and gamma

• 64 sites credentialed for IGRT by RTOG

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Spine Results

PTV HeartAxial

GammaSagittal Gamma

mean 0.99 0.94 87.7 88.4

std dev 0.04 0.15 13.8 13.2

range 0.88 – 1.23 0.67 – 1.51 22 - 100 36 - 100

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Results by Machine

Machine Manufacturer Pass Rate (%) Attempts

Criteria Failed

TLD Dose Gamma Dose and Gamma

CyberKnife 64 22 1 3 4

Elekta 56 18 0 3 5

Novalis 69 13 0 3 1

Siemens 67 3 0 1 0

TomoTherapy 79 14 0 3 0

Varian 71 68 0 16 4

Total 138 1 29 14

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Results by TPS

TPS Pass Rate (%) Attempts

Criteria Failed

TLD Dose Gamma Dose and

Gamma

CyberKinfe 64 22 1 3 4

Eclipse 68 53 0 14 3

Hi-Art 79 14 0 3 0

iPlan 71 17 0 3 2

Monaco 100 1 0 0 0

Pinnacle 68 25 0 4 4

XiO 50 6 0 2 1

total 138 1 29 14

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Results by AlgorithmAlgorithm Pass Rate

(%) AttemptsCriteria Failed

Dose Gamma Dose and Gamma

AAA 69 48 0 13 2

adapt conv/cc conv 74 23 0 4 2

Monte Carlo 67 21 0 4 3

pencil beam 74 19 0 3 2

raytracing 40 5 1 0 2

superposition 64 22 0 5 3

total 138 1 27 14CPR

Conclusions

•Challenging credentialing process

•Treatment couch should be considered in these treatments

•Cannot make generalizations with regard to machine, TPS, or algorithm

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ConclusionsConclusions

• Important QA tool• Aids improvements to IMRT delivery• All major linear accelerator and planning

systems have ability to pass

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Thank you!Thank you!

The investigation was supported by PHS grants CA10953, CA81647 and CA21661 awarded by

the NCI, DHHS.

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